The present disclosure relates to a system for reminding a person to perform an activity. The system comprise a robot configured to carry out different behaviors, wherein the activity and its corresponding trigger condition are set by a user and the system selects, from the different behaviors, a first behavior assigned to the activity, senses the person, determines, based on the sensors information, whether or not the activity is performed by the person in accordance with the trigger condition. The robot carries out the selected behavior if the activity is not performed by the person in accordance with the trigger condition, wherein after or during the selected behavior is carried out, an activity of the person is determined based on the information derived from the sensors to select a second behavior from the different behaviors.